1. Technical Field
The present invention relates to a measuring device, and more particularly to a distance measuring device.
2. Related Art
With the development of electronic technology, the laser ranging method has been widely applied in distance measurement. For example, a laser rangefinder is applied in construction, traffic management, topographical reconnaissance, indoor decoration, and other areas. The laser rangefinder is equipped with a laser beam emitter for emitting a laser beam to a target object, and a laser light receiver for receiving a signal reflected from the target object, such that the distance is measured according to the time taken for the light wave to be emitted from the laser beam emitter and received by the laser light receiver.
FIG. 1 shows a conventional two-dimensional laser rangefinder A1, which is mainly formed by a laser beam emitter A11 and a revolving mechanism A12. The laser rangefinder A1 adds a back and forth scanning angle in a horizontal direction to a laser beam emitted by the laser beam emitter A11 through the revolving mechanism A12, such that the laser rangefinder A1 can be used in a robot to achieve functions such as obstacle sensing and environment recognition. Furthermore, if a back and forth scanning angle in a vertical direction in addition to that in the horizontal direction is added, the laser rangefinder becomes a three-dimensional laser rangefinder, and the sensing range thereof becomes three-dimensional, too. As compared with the two-dimensional laser which only scans a planar range, the three-dimensional laser can scan a three-dimensional space. For example, objects such as chairs and tables having different heights and depths can be detected.
The price of three-dimensional rangefinders available in the market is very high, typically ten times higher than that of two-dimensional laser rangefinders for scanning a plane, such that three-dimensional rangefinders cannot be applied widely to various fields. Therefore, simplifying the structure of the three-dimensional rangefinder so as to overcome the problem of the excessively high cost of the conventional three-dimensional laser rangefinder such that it can be widely applied in fields such as environment recognition, environment construction, obstacle detection, and positioning of a robot, is a problem urgently requiring a solution.